1. Field of the Invention
The invention relates to an operating method for a permanent brake system of a motor vehicle and a device for performing open-loop or closed-loop control of a permanent brake system of a vehicle.
2. Description of the Related Art
Permanent brake systems for motor vehicles are known from the prior art. A permanent brake is a device that permits relatively long lasting and also wear-free braking without its braking power decreasing. Permanent brakes are divided into primary and secondary permanent brakes. A primary permanent brake is arranged on the engine side in the force flux upstream of the transmission. Permanent brakes usually act via the crankshaft of the engine and are therefore dependent on the rotational speed. Examples of the primary permanent brakes are engine brakes, for example exhaust brakes, valve-controlled permanent brakes, and/or turbo systems. Secondary permanent brakes are arranged in the force flux downstream of the transmission, for example on the Cardan shaft, and comprise, for example, hydraulically acting retarders or Eddy current brakes. Secondary permanent brakes are often dependent on the vehicle speed. Secondary permanent brakes include hydrodynamic brakes and electromagnetic Eddy current brakes.
In addition, from practice primary permanent brakes are known that have, with respect to the reaction time, a rapid component and a slow component, which can each be actuated separately. If the permanent brake system of the motor vehicle comprises both a primary permanent brake with rapid components, which are different with respect to the reaction time and a secondary permanent brake, the object arises of how an interaction between these three permanent brake components can be implemented, which is as advantageous as possible, in order to generate a corresponding permanent braking torque as a function of a permanent-brake braking request.